A Compact Circularly Polarized Antenna with Directional Pattern for Wearable Off-Body Communications

Ubaid Ullah; Ismail Ben Mabrouk; Slawomir Koziel

doi:10.1109/LAWP.2019.2942147

A Compact Circularly Polarized Antenna with Directional Pattern for Wearable Off-Body Communications

Ubaid Ullah
, Ismail Ben Mabrouk
, Slawomir Koziel

Department of Engineering

Reykjavik University

Research output: Contribution to journal › Article › peer-review

Abstract

This letter presents a geometrically simple and compact circularly polarized antenna with unidirectional radiation characteristics for off-body communications. The proposed antenna is based on a microstrip-line monopole extension from a coplanar waveguide and a protruded stub from one side of the coplanar ground plane along the length of the monopole. The orthogonal components of equal amplitudes required for circular polarization are induced using the vertical stub and the horizontal edge of the coplanar ground plane. To control the radiation of the antenna towards the human body, a flexible, high-permittivity laminated substrate is used as a reflector. The topological simplicity of the antenna permits a small number of adjustable variables and therefore a reduced computational cost of the parameter tuning process. The total footprint of the proposed antenna is only 0.23\lambda _{o}\,\times\, 0.24\lambda _{o} = 0.05 \boldsymbol{\lambda }_{\bf{o}}^2 at the lowest operating frequency. The antenna is numerically and experimentally characterized in the free space and on a real human volunteer. The simulated and measured reflection coefficient indicates that the operating range of the antenna extends from 5.16 to 6.13 GHz range with 100% bandwidth overlap between the impedance bandwidth and the axial-ratio bandwidth. The peak gain of the antenna is 6.22 dBic with a stable radiation pattern in the +z-direction, high efficiency of 90%, and 0.131 W/g specific absorption rate (SAR). The antenna can be used for Unlicensed National Information Infrastructure (U-NII) worldwide band and Industrial, Scientific, and Medical (ISM) 5.8 GHz band.

Original language	English
Article number	8844075
Pages (from-to)	2523-2527
Number of pages	5
Journal	IEEE Antennas and Wireless Propagation Letters
Volume	18
Issue number	12
DOIs	https://doi.org/10.1109/LAWP.2019.2942147
Publication status	Published - Dec 2019

Bibliographical note

Funding Information: Manuscript received June 30, 2019; revised August 20, 2019; accepted September 15, 2019. Date of publication September 18, 2019; date of current version December 19, 2019. This work was supported in part by the ADEK Award for Research Excellence (AARE) 2018, in part by the Icelandic Centre for Research (RANNIS) under Grant 174114051, and in part by the National Science Centre of Poland under Grant 2017/27/B/ST7/00563. (Corresponding author: Ubaid Ullah.) U. Ullah and I. B. Mabrouk are with the Networks and Communication Engineering Department, Al Ain University of Science and Technology, Abu Dhabi 112612, United Arab Emirates (e-mail: [email protected]; ismail. [email protected]). Publisher Copyright: © 2002-2011 IEEE.

Other keywords

Circularly polarized (CP) antenna
compact antennas
electromagnetic (EM)-driven design
wearable antenna

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10.1109/LAWP.2019.2942147

Cite this

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title = "A Compact Circularly Polarized Antenna with Directional Pattern for Wearable Off-Body Communications",

abstract = "This letter presents a geometrically simple and compact circularly polarized antenna with unidirectional radiation characteristics for off-body communications. The proposed antenna is based on a microstrip-line monopole extension from a coplanar waveguide and a protruded stub from one side of the coplanar ground plane along the length of the monopole. The orthogonal components of equal amplitudes required for circular polarization are induced using the vertical stub and the horizontal edge of the coplanar ground plane. To control the radiation of the antenna towards the human body, a flexible, high-permittivity laminated substrate is used as a reflector. The topological simplicity of the antenna permits a small number of adjustable variables and therefore a reduced computational cost of the parameter tuning process. The total footprint of the proposed antenna is only 0.23\textbackslash{}lambda \_\{o\}\textbackslash{},\textbackslash{}times\textbackslash{}, 0.24\textbackslash{}lambda \_\{o\} = 0.05 \textbackslash{}boldsymbol\{\textbackslash{}lambda \}\_\{\textbackslash{}bf\{o\}\}\textasciicircum{}2 at the lowest operating frequency. The antenna is numerically and experimentally characterized in the free space and on a real human volunteer. The simulated and measured reflection coefficient indicates that the operating range of the antenna extends from 5.16 to 6.13 GHz range with 100\% bandwidth overlap between the impedance bandwidth and the axial-ratio bandwidth. The peak gain of the antenna is 6.22 dBic with a stable radiation pattern in the +z-direction, high efficiency of 90\%, and 0.131 W/g specific absorption rate (SAR). The antenna can be used for Unlicensed National Information Infrastructure (U-NII) worldwide band and Industrial, Scientific, and Medical (ISM) 5.8 GHz band.",

keywords = "Circularly polarized (CP) antenna, compact antennas, electromagnetic (EM)-driven design, wearable antenna",

author = "Ubaid Ullah and Mabrouk, \{Ismail Ben\} and Slawomir Koziel",

note = "Funding Information: Manuscript received June 30, 2019; revised August 20, 2019; accepted September 15, 2019. Date of publication September 18, 2019; date of current version December 19, 2019. This work was supported in part by the ADEK Award for Research Excellence (AARE) 2018, in part by the Icelandic Centre for Research (RANNIS) under Grant 174114051, and in part by the National Science Centre of Poland under Grant 2017/27/B/ST7/00563. (Corresponding author: Ubaid Ullah.) U. Ullah and I. B. Mabrouk are with the Networks and Communication Engineering Department, Al Ain University of Science and Technology, Abu Dhabi 112612, United Arab Emirates (e-mail: [email protected]; ismail. [email protected]). Publisher Copyright: {\textcopyright} 2002-2011 IEEE.",

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doi = "10.1109/LAWP.2019.2942147",

language = "English",

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journal = "IEEE Antennas and Wireless Propagation Letters",

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N1 - Funding Information: Manuscript received June 30, 2019; revised August 20, 2019; accepted September 15, 2019. Date of publication September 18, 2019; date of current version December 19, 2019. This work was supported in part by the ADEK Award for Research Excellence (AARE) 2018, in part by the Icelandic Centre for Research (RANNIS) under Grant 174114051, and in part by the National Science Centre of Poland under Grant 2017/27/B/ST7/00563. (Corresponding author: Ubaid Ullah.) U. Ullah and I. B. Mabrouk are with the Networks and Communication Engineering Department, Al Ain University of Science and Technology, Abu Dhabi 112612, United Arab Emirates (e-mail: [email protected]; ismail. [email protected]). Publisher Copyright: © 2002-2011 IEEE.

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N2 - This letter presents a geometrically simple and compact circularly polarized antenna with unidirectional radiation characteristics for off-body communications. The proposed antenna is based on a microstrip-line monopole extension from a coplanar waveguide and a protruded stub from one side of the coplanar ground plane along the length of the monopole. The orthogonal components of equal amplitudes required for circular polarization are induced using the vertical stub and the horizontal edge of the coplanar ground plane. To control the radiation of the antenna towards the human body, a flexible, high-permittivity laminated substrate is used as a reflector. The topological simplicity of the antenna permits a small number of adjustable variables and therefore a reduced computational cost of the parameter tuning process. The total footprint of the proposed antenna is only 0.23\lambda _{o}\,\times\, 0.24\lambda _{o} = 0.05 \boldsymbol{\lambda }_{\bf{o}}^2 at the lowest operating frequency. The antenna is numerically and experimentally characterized in the free space and on a real human volunteer. The simulated and measured reflection coefficient indicates that the operating range of the antenna extends from 5.16 to 6.13 GHz range with 100% bandwidth overlap between the impedance bandwidth and the axial-ratio bandwidth. The peak gain of the antenna is 6.22 dBic with a stable radiation pattern in the +z-direction, high efficiency of 90%, and 0.131 W/g specific absorption rate (SAR). The antenna can be used for Unlicensed National Information Infrastructure (U-NII) worldwide band and Industrial, Scientific, and Medical (ISM) 5.8 GHz band.

AB - This letter presents a geometrically simple and compact circularly polarized antenna with unidirectional radiation characteristics for off-body communications. The proposed antenna is based on a microstrip-line monopole extension from a coplanar waveguide and a protruded stub from one side of the coplanar ground plane along the length of the monopole. The orthogonal components of equal amplitudes required for circular polarization are induced using the vertical stub and the horizontal edge of the coplanar ground plane. To control the radiation of the antenna towards the human body, a flexible, high-permittivity laminated substrate is used as a reflector. The topological simplicity of the antenna permits a small number of adjustable variables and therefore a reduced computational cost of the parameter tuning process. The total footprint of the proposed antenna is only 0.23\lambda _{o}\,\times\, 0.24\lambda _{o} = 0.05 \boldsymbol{\lambda }_{\bf{o}}^2 at the lowest operating frequency. The antenna is numerically and experimentally characterized in the free space and on a real human volunteer. The simulated and measured reflection coefficient indicates that the operating range of the antenna extends from 5.16 to 6.13 GHz range with 100% bandwidth overlap between the impedance bandwidth and the axial-ratio bandwidth. The peak gain of the antenna is 6.22 dBic with a stable radiation pattern in the +z-direction, high efficiency of 90%, and 0.131 W/g specific absorption rate (SAR). The antenna can be used for Unlicensed National Information Infrastructure (U-NII) worldwide band and Industrial, Scientific, and Medical (ISM) 5.8 GHz band.

KW - Circularly polarized (CP) antenna

KW - compact antennas

KW - electromagnetic (EM)-driven design

KW - wearable antenna

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DO - 10.1109/LAWP.2019.2942147

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JO - IEEE Antennas and Wireless Propagation Letters

JF - IEEE Antennas and Wireless Propagation Letters

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M1 - 8844075

ER -

A Compact Circularly Polarized Antenna with Directional Pattern for Wearable Off-Body Communications

Abstract

Bibliographical note

Other keywords

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